Ivana Trump and Donald Trump at the U.S. Open Tennis Tournament in 1988. Picture: PL Gould/IMAGES/Getty ImagesSource:Getty Images

Her fast-food-loving ex doesn’t have the same discipline, despite her nagging.

“I can tell him 100 times, but he does what he wants anyway,” says Ivana, who says she saw the Donald’s weight creep up over the years from about 178 to 225 pounds (80kg - 102kg). Still, she says he’s not in bad shape.

“He looks very, very good and is very healthy — his only weakness is the Big Mac, what can I tell you?”

“None of my kids are obese — they’re all tall and slim and handsome and smart. And the grandkids are exactly the same — good genes.”

She has a harsh message for parents struggling with their weight.

“If you are an obese parent, I guarantee your child will be obese,” says Ivana, who says she had little time to cook for her children when they were young because she was running Atlantic City casinos and the Plaza. “If you’re a lazy person, it’s much harder — you have to be committed to a certain regimen and stick to it.”

She first met Mech, 48, a few years ago through mutual friends, and they instantly clicked.

“I love Italians — they are bad boys. They love to eat, but they eat well,” she says. “I was married to two Italians and dated many.” (Ivana has had four husbands.)

But, she was initially sceptical about working together.

“I said, ‘How can I be spokesperson for obesity? I’m slim,’” she says. “Who wants to walk around with 300 extra pounds [136kg]? It’s not healthy — you are lazy, you’re glued to the television.”

But, she fell in love with Mech’s products, especially the praline cookies, which she’d have shipped over from Italy to serve at parties.

“I leave them all around the house,” she says. “It tastes exactly the same as a praline, except it’s 60 calories versus 400 calories.”

Mech’s products use artificial sweeteners such as polydextrose and erythrol, and pea and soy protein are also common ingredients.

In Italy, his program is known as La Dieta Tisanoreica, and many items contain a proprietary blend of various fruit extracts and herbs, including griffonia seeds, which Mech calls his “secret weapon” for their purported fat-fighting, mood-boosting properties.

Items can be purchased individually, or dieters can sign up for a program of four meals a day for $US20.

The program has been popular in Italy for years, and Mech says Silvio Berlusconi lost 10 pounds in a week on it. He’s confident that with Ivana’s help, it will be successful here.

“When she was married to Donald Trump, she helped him build one of the biggest companies in the world — I know she will do the same with the Italiano Diet,” he says. “She has more energy than a Maserati.”